1. Field of the Invention
This invention relates to automatic redialing systems for telephones and particularly to a system for automatically inserting the universal long distance prefix in the form of the numeral "1" before a last number dialed memory recorded number.
2. Prior Art
Examples of U.S. patents that relate to the general field of telephone apparatus using microprocessor electronic circuitry are
U.S. Pat. No. 3,804,984, issued Apr. 16, 1974 (Yachabach); PA1 U.S. Pat. No. 4,008,379, issued Feb. 15, 1977 (Watkins); PA1 U.S. Pat. No. 4,032,722, issued Jun. 28, 1977 (Connolly et al.); PA1 U.S. Pat. No. 4,119,810, issued Oct. 10, 1978 (Marin et al.). PA1 U.S. Pat. No. 3,920,926, issued Nov. 18, 1975 (Lenaerts et al.); PA1 U.S. Pat. No. 3,932,709, issued Jan. 13, 1976 (Hoff et al.); PA1 U.S. Pat. No. 4,008,380, issued Feb. 15, 1977 (La Borde); PA1 U.S. Pat. No. 4,029,908, issued Jun. 14, 1977 (Moseley et al.); PA1 U.S. Pat. No. 4,119,810, issued Oct. 10, 1978 (Marin et al.); PA1 U.S. Pat. No. 4,243,845, issued Jan. 6, 1981 (Feinberg et al.); PA1 U.S. Pat. No. 4,324,954, issued Apr. 13, 1982 (Taylor).
The following U.S. patents disclose microprocessor electronic telephone circuits that provide for storing the last number dialed in a memory and redialing that number by activation of the memory:
These patents did not specifically confront the problem solved by applicant or at least did not provide as simple and practical a solution.